Display control apparatus, control method therefor, and non-transitory computer-readable storage medium

ABSTRACT

When rendering a graphic according to the locus of an input position, it is determined whether a region which has been preset for the graphic to be rendered, and has the start position of the continuous input as a reference overlaps a region preset for an already rendered graphic by a predetermined amount or more. If it is determined that the regions do not overlap each other by the predetermined amount or more, a graphic is rendered according to the locus of the input position. Alternatively, if it is determined that the regions overlap each other by the predetermined amount or more, control is switched to remove the already rendered graphic according to the locus of the input position.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technique of rendering a graphic atan input position on a screen, or removing a graphic rendered at theposition.

2. Description of the Related Art

Recent portable devices such as digital cameras or mobile phones havinga camera enable a user to add various effects to a captured image ormoving image. A mobile phone, for example, allows the user to placeicons such as graphics, handwritten characters, and the like on acaptured image, attach the generated image to an e-mail message, andthen transmit it to another user. In recent years, some of theabove-described portable devices adopt a touch panel display as adisplay device, thereby enabling the user to more intuitionally placegraphics, characters, and the like on an image.

When placing a graphic within an image or moving image, the user mayerroneously place the graphic at an undesired location. Some of theabove-described devices, therefore, have a function of removing analready placed graphic. The above-described portable devices often havea small display device, and display only a limited number of menus suchas recently used functions to make an image rendering region as large aspossible. In such a portable device, to select a menu for removing agraphic and actually delete the graphic, the user needs to performcomplicated operations.

Japanese Patent Laid-Open No. 07-200133 has disclosed an input devicewhich uses a pen-based user interface and switches between an input modeand a removal mode depending on a pen tip width.

Graphics placed within an image or moving image may overlap each other.If graphics overlap each other, it is difficult to view the graphicssuch that they are identifiable. More specifically, when animation isset for the placed graphics, it is difficult to identify the graphics,which may not give additional effects but cause user discomfort.

Japanese Patent Laid-Open No. 2001-188525 has disclosed the followingtechnique. That is, when a new image is instructed to be placed at aposition which falls within a region that has been set based on theshape of an image, prohibited from overlapping, of those placed withinan image, the new image is controlled to be placed in a blank regionother than that region.

When an input device switches between an input mode and a removal modedepending on a pen tip width as described in Japanese Patent Laid-OpenNo. 07-200133, however, the input device requires a special input userinterface and, therefore, is not a general-purpose device.

When an image is placed in a blank region other than a region which hasbeen set based on the shape of an image prohibited from overlapping asdescribed in Japanese Patent Laid-Open No. 2001-188525, the image isplaced at a position different from that desired by the user and,therefore, the user may have the impression that it is inconvenient.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the aboveproblems of the conventional techniques. The present invention providesa technique of facilitating removing a graphic already rendered in animage. The present invention also provides a technique of generating animage in which graphics have been rendered at desired positions whileavoiding the graphics from overlapping.

The present invention in its first aspect provides a display controlapparatus comprising: a position input unit configured to input aposition on a screen of a display device; a rendering unit configured torender a graphic according to a locus of the input position input by theposition input unit; a first determination unit configured to determinewhether a predetermined region having, as a reference, a start positionof one input performed by the position input unit overlaps a regionpreset for the graphic already rendered by the rendering unit by notless than a predetermined amount; and a control unit configured tocontrol, when the first determination unit determines that thepredetermined region having the start position as a reference does notoverlap the preset region by not less than the predetermined amount, tocause the rendering unit to render a graphic according to the locus ofthe input position, and to control, when the first determination unitdetermines that the predetermined region having the start position as areference overlaps the preset region by not less than the predeterminedamount, to remove the graphic already rendered by the rendering unitaccording to the locus of the input position.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the functional configuration of adigital video camera 100 according to an embodiment of the presentinvention;

FIGS. 2A, 2B, 2C, 2D, 2E, and 2F are views each showing a GUI forexplaining rendering tools according to the embodiment of the presentinvention;

FIG. 3 is a flowchart illustrating rendering control processingaccording to the embodiment of the present invention;

FIGS. 4A and 4B are views for explaining input start positionoverlapping determination according to the embodiment of the presentinvention;

FIG. 5 is a view for explaining conditional expressions for overlappingdetermination according to the embodiment of the present invention;

FIGS. 6A and 6B are flowcharts illustrating rendering mode processingand removal mode processing, respectively, according to the embodimentof the present invention;

FIGS. 7A and 7B are views for explaining a rendering mode and a removalmode, respectively, according to the embodiment of the presentinvention; and

FIGS. 8A, 8B, 8C, and 8D are views for explaining input positionoverlapping determination according to the embodiment of the presentinvention.

DESCRIPTION OF THE EMBODIMENTS

A preferred embodiment of the present invention will be described indetail below with reference to the accompanying drawings. In theembodiment to be described below, a case in which the present inventionis applied to a digital video camera capable of rendering or removing agraphic depending on an input position on a screen will be explained.The present invention, however, is applicable to an arbitrary devicecapable of rendering or removing a graphic depending on an inputposition on a screen.

FIG. 1 is a block diagram showing the functional configuration of adigital video camera 100 according to the embodiment of the presentinvention.

A system control unit 101 is, for example, a CPU which controls theoperation of each block of the digital video camera 100. Morespecifically, the system control unit 101 controls the operation of eachblock by reading out an operation program stored in, for example, anon-volatile memory 114 for each block of the digital video camera 100,expanding the program on a system memory 113, and executing it. Thenon-volatile memory 114 is, for example, an electrically erasableprogrammable memory such as an EEPROM, which stores parameters and thelike necessary for the operation of each block of the digital videocamera 100 in addition to the operation program of each block. Thesystem memory 113 is, for example, a RAM which is used as not only anexpansion area for the operation program of each block of the digitalvideo camera 100 but also an area for temporarily storing intermediatedata and the like output in the operation of each block.

In the embodiment, the operation program of each block of the digitalvideo camera 100 controls the operation of the block. The presentinvention, however, is not limited to this, and each block may include acircuit which executes the same processing as that of a correspondingoperation program.

A photographing lens 104 comprises a photographing lens group of thedigital video camera 100 including a focus lens, and images an opticalimage on an image capturing unit 106 via an aperture stop and a shutter105 having an ND filter function. The image capturing unit 106 is, forexample, an image sensor such as a CCD or CMOS sensor, which convertsthe optical image imaged via the photographing lens 104 into an analogimage signal, and outputs it to an A/D converter 107. The A/D converter107 performs A/D conversion processing for the analog image signal inputfrom the image capturing unit 106, and converts the analog image signalinto a digital image signal (an image). A barrier 103 covers an imagingoptical system including the photographing lens 104, shutter 105, andimage capturing unit 106, thereby preventing the imaging optical systemfrom being soiled or damaged.

An image processing unit 102 executes predetermined pixel interpolation,resizing processing such as reduction processing, or color conversionprocessing for an image output from the A/D converter 107 or an imageread out from a memory 109 by a memory control unit 108 (to be describedlater). Furthermore, the image processing unit 102 executes computationprocessing associated with exposure control and focus detection controlusing an image which has been input by the A/D converter 107 uponcapturing, and outputs the computation result to the system control unit101. Based on the computation result, the system control unit 101performs exposure control and focus detection control by operating thephotographing lens 104 and shutter 105 using a driving system (notshown).

Assume that the digital video camera 100 of this embodiment adopts TTL(Through-The-Lens) AF (Auto Focus) processing and AE (Auto Exposure)processing. Note that the AE processing controls the shutter speed, theaperture stop, the ND filter, and a gain applied to a digital imagesignal in the image processing unit 102. The image processing unit 102executes predetermined computation processing using captured image data,and also executes TTL AWB (Auto White Balance) processing based on theobtained computation result.

Assume that when the digital video camera 100 is used in a normal modein which a moving image is captured, it executes the AF processing, AEprocessing and AWB processing in real time. When an automatic executionsetting for each processing is canceled, however, it is possible tomanually set parameters for each processing.

The memory control unit 108 controls an operation of reading outinformation from the memory 109, and an operation of writing informationin the memory 109. The memory control unit 108 writes, in the memory109, a digital image signal input from the A/D converter 107 or an imagesignal which have undergone various processes and then output by theimage processing unit 102. Assume that the memory 109 is designed tohave an enough storage capacity for storing information since audioinformation in capturing a moving image is also written in addition toan image group associated with the frames of the moving image incapturing the moving image.

In addition to a captured image, a display image to be displayed on adisplay unit 111 (to be described later) is written in the memory 109.To display the display image on the display unit 111, the memory controlunit 108 reads out the display image from the memory 109, and outputsthe image to a D/A converter 110 (to be described later) for displayingit on the display unit 111.

The D/A converter 110 executes D/A conversion processing for an inputdigital image signal, and outputs the obtained analog image signal tothe display unit 111, which then displays it. The display unit 111serves as, for example, a display device such as a compact LCD, whichdisplays an analog image signal output from the D/A converter 110. Thedisplay unit 111 functions as an electronic viewfinder by inputting, tothe D/A converter 110, digital image signals successively output fromthe A/D converter 107 upon capturing, converting them into analog imagesignals again, and displaying (live-view displaying) them on the displayunit 111.

A system timer 112 is a timer incorporated in the digital video camera100, which is, for example, used to obtain a time stamp or measure anelapsed time in each program or process executed by the system controlunit 101.

An operation input unit 115 is a user interface such as a power button,a mode selection SW, or a release button included in the digital videocamera 100, which analyzes an operation input by the user operation ofeach operation member, and transmits the input operation to the systemcontrol unit 101.

Assume that the display unit 111 of the embodiment is a touch paneldisplay, and the operation input unit 115 also detects a touch inputperformed on a touch panel, such as an input operation for a GUI buttondisplayed on the display unit 111. The display unit 111 includes adisplay device and a touch panel. The touch panel is made of atransparent material so that display of the display unit 111 is visible,and is attached on the display surface of the display device. Theposition of a touch input on the touch panel on the display device,which is detected by the operation input unit 115, corresponds to aposition on the screen of the display device. When a touch input isperformed, the operation input unit 115 detects the position of thetouch input as coordinates on the screen. Note that the operation inputunit 115 can detect a touch input by assigning the touch input to one ofthe following states (operations) according to a continuation state andthe movement speed of an input position.

touchdown: a state at the moment when a touch input is recognized

touchon: a state in which a state wherein a touch input is recognizedcontinues for a predetermined period of time or longer

move: a state in which a touchon is detected and an input point is beingmoved by a predetermined distance or longer or being moved at apredetermined speed or higher (such as dragging)

touchup: a state at the moment when, since an input position is notrecognized for a predetermined period of time or longer, it isdetermined that an input operation has been stopped

flick: a state in which a touchup is performed immediately after movingat a predetermined speed or higher (such as flicking by a finger)

touchoff: a state in which a touch input is not performed

tap: a state in which after a touchdown, a move is not detected but atouchup is detected (a single touch)

In the embodiment, each process executed by the digital video camera 100will be described using the above-described seven states. The statenames and designation of a state as a trigger for each process aremerely examples, and the present invention is not limited to them.

Although a case in which the operation input unit 115 detects a touchinput performed on the touch panel has been described in thisembodiment, the present invention is not limited to this. That is, forthe touch panel, various types of touch panel can be used, such as aresistance film type touch panel, a static capacitance type touch panel,a surface acoustic wave type touch panel, an infrared type touch panel,an electromagnetic induction type touch panel, an image recognition typetouch panel, and an optical sensor type touch panel. An input to bedetected depends on the type of touch panel. That is, when an input isdetected without directly touching the touch panel according to the typeof touch panel, the operation input unit 115 detects the input andtransmits it to the system control unit 101.

A storage medium I/F 116 is an interface for connecting the digitalvideo camera 100 to a storage medium 117, such as a memory card or HDD,which is a storage device detachably connected to the digital videocamera 100. The storage medium 117 records, via the storage medium I/F116, the image and voice of a moving image which has been encoded by theimage processing unit 102 according to a predetermined encoding scheme.

(GUIs for Rendering Tools)

Rendering tools displayed on the display unit 111 of the digital videocamera 100 of the embodiment will be explained with reference to FIGS.2A, 2B, 2C, 2D, 2E, and 2F. A rendering tool is used when the userrenders an overlapping line and graphic on a captured image live-viewdisplayed on the display unit 111. When recording a moving image, it ispossible to reflect and record a graphic and the like which has beenrendered using a rendering tool.

FIG. 2A shows a state in which a tool bar for various settings of therendering tools is displayed on the display unit 111. The tool barincludes five icons, that is, a rendering tool selection icon 201, aline type selection icon 202, a color selection icon 203, a stampselection icon 204, and an animation stamp selection icon 205. When theuser taps each icon, it is possible to transit to a setting or selectionGUI corresponding to each item.

FIG. 2B shows a rendering tool selection GUI which is displayed when theuser taps the rendering tool selection icon 201. When the user selectsone of a pen 211, a crayon 212, a writing brush 213, a paint brush 214,and a spray 215, the user can render a line segment. Note that when theuser selects an item for rendering a line segment in the rendering toolselection GUI, the user can make a corresponding setting by tapping theline type selection icon 202 or color selection icon 203 to transit to aGUI shown in FIG. 2C or 2D. The rendering tool selection GUI alsoincludes an eraser 216 for removing a rendered object (a line segment, agraphic, or the like).

FIGS. 2E and 2F show selection GUIs to which the screen transits whenthe user taps the stamp selection icon 204 and the animation stampselection icon 205, respectively. Unlike the above-described tools forrendering a line segment, a stamp or animation stamp enables to place apreset graphic or a character string graphic such as a capture time. Theanimation stamp indicates a stamp for rendering a graphic which changesover time.

As described above, when the user selects a rendering tool or stampusing a GUI, he/she can perform rendering on a captured image beinglive-view displayed. More specifically, by setting as a start position apointing position at which a touchdown is detected, a line segment orgraphic is rendered according to a locus (locus of a “move” operation)which is continuously input from the start position in one inputoperation, that is, from when the touchdown is detected until a touchupis detected.

(Rendering Control Processing)

Rendering control processing by the digital video camera 100 having theabove-described configuration according to the embodiment will bedescribed in detail with reference to a flowchart shown in FIG. 3. It ispossible to implement processing corresponding to the flowchart when thesystem control unit 101 reads out a corresponding processing programstored in, for example, the non-volatile memory 114, expands the programon the system memory 113, and executes it. Assume that the renderingcontrol processing starts when the user operates the mode selection SWof the operation input unit 115 to set to a special capture mode forcapturing a moving image in which an object is placed within its frame.

In step S301, the system control unit 101 determines whether the userhas performed, on the display unit 111, a touch input for rendering orremoving an object. More specifically, the system control unit 101determines whether selection of a rendering tool is complete and theoperation input unit 115 has detected a “touchdown” operation at aposition within an image live view display region. If a touch input hasbeen performed, the system control unit 101 advances the process to stepS302; otherwise, the system control unit 101 repeats the processing instep S301 until a touch input is performed. The rendering controlprocessing will be explained below by assuming that an animation stamphas been selected as a rendering tool.

In step S302, the system control unit 101 determines whether thereexists a graphic already rendered at a pointing start position where the“touchdown” operation has been detected in step S301. More specifically,the system control unit 101 determines whether a region (pointingregion) whose center is at the pointing start position and which has apreset size for a graphic to be rendered overlaps a region (renderedregion) preset for an already rendered graphic.

If the system control unit 101 determines that, as shown in FIG. 4A, agraphic has already been rendered in the image live view display regionand a pointing region 401 and a rendered region 402 associated with thealready rendered graphic do not overlap each other, the process advancesto step S303. Alternatively, if the system control unit 101 determinesthat, as shown in FIG. 4B, the rendered region 402 and the pointingregion 401 overlap each other, the process advances to step S306.

If both the pointing region and the rendered region are rectangular, itis possible to use the coordinates of the diagonal points positioned atthe upper left corner and lower right corner of each region to make thedetermination whether the regions overlap each other. If, for example,two regions A and B overlap each other as shown in FIG. 5, the followingfour conditional expressions simultaneously hold.

XAleft<XBright  (1)

XBleft<XAright  (2)

YBbottom<YAtop  (3)

YAbottom<YBtop  (4)

That is, if the four conditions hold, the system control unit 101determines that the regions overlap each other. Assume, in thisembodiment, that it is determined based on the above-describedconditional expressions whether a rectangular region preset for eachgraphic rendered in the image live view display region overlaps a regionwhose center is a pointing start position and which has been preset fora graphic to be rendered. In this case, when a graphic is rendered, thesystem control unit 101 acquires information of a region preset for thegraphic, and stores it in the system memory 113. The present invention,however, is not limited to this, and a rendered region and a pointingregion need not be rectangular, and may have an arbitrary shape.

The region which has been preset for a graphic to be rendered and whichis assigned as a pointing region need not be a region whose center is ata position where the “touchdown” operation is detected, and may be aregion having, as a reference, the position where the “touchdown”operation is detected which is placed at the upper left coordinates ofthe region. Furthermore, the pointing region or rendered region mayalways have the same size, or may have a size set depending on the sizeof a graphic to be rendered such as the size of a transparent region ofa graphic to be rendered or an already rendered graphic.

In step S303, the system control unit 101 determines that an operationinput in the image live view display region is associated with renderingof a graphic, and renders a graphic selected in the animation stampselection GUI at the position where the “touchdown” operation isdetected. At this time, simultaneously with setting a new renderingtimer in the system timer 112 and starting it, the system control unit101 newly sets and starts a removal timer for counting a time until therendered graphic is automatically removed, which has been preset for therendered graphic. The system control unit 101 also stores, in the systemmemory 113, coordinate information of the rendered region set for therendered graphic.

Assume that for each graphic rendered in the image live view displayregion, a time until the graphic is automatically removed has beenpreset in the digital video camera 100 of the embodiment. This isbecause a capture angle and the state of an object may change duringcapturing of a moving image, thereby eliminating the need for renderinga graphic. A time until a graphic is automatically removed may be aconstant time or a different time for each type of stamp or each stampsize. In this embodiment, for descriptive convenience, assume that aconstant value of 10 sec has been set as a time until a graphic isautomatically removed.

After that, the system control unit 101 executes rendering modeprocessing in step S304. The rendering mode processing is repeatedlyexecuted until the system control unit 101 determines in step S305 thata “touchup” operation has been detected.

(Rendering Mode Processing)

The rendering mode processing of the embodiment which is executed whenit is determined that an operation input in the image live view displayregion is associated with rendering of a graphic will be described withreference to a flowchart shown in FIG. 6A.

In step S601, the system control unit 101 determines whether a renderingtimer set in the system timer 112 has exceeded 250 ms. In thisembodiment, when one input continues as shown in FIG. 7A, a graphic isrendered at a given interval (250 ms) according to the locus of acontinuously input position. That is, the system control unit 101determines in step S601 whether to render a next graphic. If the systemcontrol unit 101 determines that the rendering timer has exceeded 250ms, the process advances to step S602; otherwise, the process advancesto step S605.

In step S602, the system control unit 101 resets and restarts the countof the rendering timer set in the system memory 113.

In step S603, the system control unit 101 determines whether a pointingregion whose center is at a position where an input is currentlyperformed in the display unit 111 overlaps a rendered region associatedwith an already rendered graphic. If the system control unit 101determines that the pointing region and the rendered region do notoverlap each other, the process advances to step S604; otherwise, theprocess advances to step S605.

In this embodiment, if, as shown in FIG. 8C, a rendered region 812 and apointing region 811 whose center is at a position where an input isperformed do not overlap each other, the system control unit 101determines that it is possible to render a new graphic. Alternatively,assume that the pointing region 811 and the rendered region 812 overlapeach other, as shown in FIG. 8D. In this case, if the system controlunit 101 renders a new graphic, the graphic overlaps the alreadyrendered graphic. The system control unit 101, therefore, determinesthat no graphic is rendered.

In step S604, the system control unit 101 renders a graphic selected inthe animation stamp selection GUI at the position where the input isperformed, newly sets a removal timer for the graphic in the systemtimer 112, and starts it.

In step S605, the system control unit 101 determines whether there is agraphic, of already rendered graphics, whose removal timer set in thesystem timer 112 has exceeded 10 sec. If the system control unit 101determines that there is a graphic to be automatically removed, theprocess advances to step S606 to stop rendering of the graphic and endthe rendering mode processing; otherwise, the rendering mode processingends.

With this operation, the rendering mode processing of the embodiment canplace a new graphic in the image live view display region whilecontrolling to render the new graphic so as not to overlap an alreadyrendered graphic. That is, even in a “move” operation whose movementspeed is low, it is possible to control to render a new graphic so asnot to overlap an already rendered graphic without forcibly rendering agraphic at a given interval.

If it is determined in step S302 of the rendering control processingthat the pointing region and the rendered region overlap each other, thesystem control unit 101 executes the following processing. That is, thesystem control unit 101 determines in step S306 that the operation inputin the image live view display region is associated with removal of analready rendered graphic, and executes a removal mode processing. Notethat the removal mode processing is repeatedly executed until the systemcontrol unit 101 determines that a “tap” operation has been detected instep S307.

(Removal Mode Processing)

The removal mode processing of the embodiment which is executed when itis determined that an operation input in the image live view displayregion is associated with removal of an already rendered graphic will bedescribed with reference to a flowchart shown in FIG. 6B.

In step S611, the system control unit 101 determines whether a pointingregion whose center is at a position where an input is currentlyperformed in the display unit 111 overlaps a rendered region associatedwith an already rendered graphic. If the system control unit 101determines that the pointing region and the rendered region overlap eachother, the process advances to step S612; otherwise, the removal modeprocessing ends.

In step S612, the system control unit 101 removes a graphic associatedwith the rendered region which overlaps the pointing region, and endsthe removal mode processing. That is, if already rendered graphics existin the image live view display region as shown in FIG. 7A, the user canremove the graphics by performing a “move” operation shown in FIG. 7Bfor the graphics.

With this operation, the removal mode processing of the embodiment canomit a complicated operation for selecting a graphic removal tool whenremoving already rendered graphics. Unlike a tool for rendering a linesegment, it is possible to reliably remove rendered graphics byperforming a “move” operation once without repeatedly performing a“move” operation on already rendered graphics using the eraser tool forremoving graphics.

In this embodiment, whether a rendered region and a pointing region upondetecting a touchdown overlap each other, and whether a rendered regionand a pointing region whose center is at a position where an input isperformed in a “move” operation overlap each other are determined.Overlapping determination for the two regions may not be limited todetermination of whether the regions overlap each other.

For example, if both the pointing region and the rendered region arerectangular as shown in this embodiment, no graphic may be rendered nearthe vertices of the rectangular regions. Even if, therefore, one regionoverlaps the other region at its vertex, graphics may not overlap eachother. In this case, the user may not be able to render a graphic at adesired position, or a removal mode may be unwantedly set. Therefore, inoverlapping determination, it may be determined whether two regionsoverlap each other by a predetermined amount or more.

As described above, the display control apparatus of the embodiment canfacilitate removing a graphic already rendered in an image.Alternatively, the apparatus can generate an image in which graphicshave been rendered at desired positions while avoiding the graphics fromoverlapping. More specifically, when rendering a graphic according tothe locus of a continuously input position, the display controlapparatus determines whether a region which has been preset for agraphic to be rendered, and has the start position of a continuous inputas a reference overlaps a region preset for an already rendered graphicby a predetermined amount or more. If the apparatus determines that theregions do not overlap each other by the predetermined amount or more,it renders a graphic according to the locus of the input position;otherwise, control is switched to remove already rendered graphicsaccording to the locus of the input position. When rendering a graphicaccording to the locus of the position, it is determined whether aregion which has been preset for the graphic to be rendered, and has theinput position as a reference overlaps a region preset for an alreadyrendered graphic by a predetermined amount or more. If it is determinedthat the regions overlap each other, the apparatus controls not torender the graphic.

With this operation, an operation of rendering a graphic or an operationof removing a graphic is automatically selected depending on a situationwithout performing a complicated operation. The user, therefore, canreadily render and remove a graphic in a similar operation. Furthermore,since determination is made so that a graphic is rendered not to overlapan already rendered graphic, it is possible to generate an image whichdoes not give the user the impression that it is hard to see.

(Modification)

In the rendering mode processing of the above-described embodiment, ifit is determined that a pointing region whose center is at an inputposition does not overlap a rendered region associated with an alreadyrendered graphic, no new graphic is rendered. In this case, for example,if a time for automatically removing a rendered graphic is set, thefollowing situation may occur.

When, for example, a graphic rendering instruction is given across analready rendered graphic group 801 as shown in FIG. 8A, no new graphicis rendered on the graphic group 801. After that, if all the graphics ofthe graphic group 801 are automatically removed, the user may have theimpression that the graphics rendered after the graphic group 801 areseparated as shown in FIG. 8B although they have been continuouslyrendered.

To avoid such situation, if it is determined that a pointing regionwhose center is at an input position overlaps a rendered regionassociated with an already rendered graphic, the system control unit 101need only perform the following processing. More specifically, thesystem control unit 101 need only specify a graphic associated with therendered region which has been determined to overlap the pointingregion, reset a removal timer for the graphic which has been set in thesystem timer 112, and restart counting.

With this operation, even if it is determined that an already renderedgraphic overlaps a pointing region whose center is at an input position,it is possible to reset a time until the graphic is automaticallyremoved. That is, even if there exists an already rendered graphic onthe locus of the continuously input position when rendering a graphicaccording to the locus, it is possible to present the already renderedgraphic as if it has been rendered according to the continuously inputposition.

In consideration of a change in capture angle or state of an objectduring capturing of a moving image, the user may desire to render agraphic according to the locus of a newly continuously input position.In this case, in the rendering mode processing, if there exists agraphic associated with a rendered region which has been determined tooverlap a pointing region whose center is at an input position, thegraphic may be removed, and a new graphic may be rendered at the inputposition.

In the above-described embodiment, a case in which an animation stamp isrendered as a graphic has been explained. When inputting a drawn linesegment like a pen tool, separation of the drawn line may be undesiredlike a handwritten character. Assume that an input operation isperformed to render a line segment. In this case, even if there existsan already rendered graphic or line segment, control may be performed toforcibly render a line segment at an input position.

Although the digital video camera 100 having a touch panel has beenexplained in this embodiment, the present invention is not limited tothis, and is applicable to another device which has a UI for instructingan input of a position on a screen and can perform graphic renderingaccording to the input. That is, the present invention is not limited toa touch input performed on a touch panel, and is applicable to anydevice which can perform rendering by the user operation of a pointingdevice for performing a position input on a display screen. For example,it is readily understood that when a PC is used as a display controlapparatus, an operation performed on the above-described touch panel maybe associated with an operation performed using a mouse. In this case,the operation performed using the mouse need only be associated withthat performed on the touch panel as follows:

-   -   pressing the left button of the mouse: a “touchdown” in a touch        operation;    -   a state in which the left button of the mouse is pressed: a        “touchon” in a touch operation;    -   an operation of releasing the left button of the mouse after        pressing the left button: a “touchup” in a touch operation;    -   a state in which the left button of the mouse is not pressed: a        “touchoff” in a touch operation; and    -   a drag operation of the mouse (an operation of moving the mouse        while pressing the left button): a “move” in a touch operation.

One hardware component may control the system control unit 101 or aplurality of hardware components may share the processing, therebycontrolling the apparatus as a whole.

The present invention has been described in detail based on thepreferred embodiment. The present invention, however, is not limited tothe specific embodiment, and includes various modes within the spiritand scope of the present invention. The above-described embodiments aremerely examples, and can be combined as needed.

Other Embodiments

Aspects of the present invention can also be realized by a computer of asystem or apparatus (or devices such as a CPU or MPU) that reads out andexecutes a program recorded on a memory device to perform the functionsof the above-described embodiment(s), and by a method, the steps ofwhich are performed by a computer of a system or apparatus by, forexample, reading out and executing a program recorded on a memory deviceto perform the functions of the above-described embodiment(s). For thispurpose, the program is provided to the computer for example via anetwork or from a recording medium of various types serving as thememory device (for example, computer-readable medium).

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2010-283733, filed Dec. 20, 2010, which is hereby incorporated byreference herein in its entirety.

1. A display control apparatus comprising: a position input unitconfigured to input a position on a screen of a display device; arendering unit configured to render a graphic according to a locus ofthe input position input by said position input unit; a firstdetermination unit configured to determine whether a predeterminedregion having, as a reference, a start position of one input performedby said position input unit overlaps a region preset for the graphicalready rendered by said rendering unit by not less than a predeterminedamount; and a control unit configured to control, when said firstdetermination unit determines that the predetermined region having thestart position as a reference does not overlap the preset region by notless than the predetermined amount, to cause said rendering unit torender a graphic according to the locus of the input position, and tocontrol, when said first determination unit determines that thepredetermined region having the start position as a reference overlapsthe preset region by not less than the predetermined amount, to removethe graphic already rendered by said rendering unit according to thelocus of the input position.
 2. The apparatus according to claim 1,further comprising: a second determination unit configured to determine,while one input performed by said position input unit continues, whethera predetermined region having, as a reference, a position where theinput is performed overlaps the region preset for the graphic alreadyrendered by said rendering unit by not less than a predetermined amount,wherein when said first determination unit determines that thepredetermined region having the start position as a reference does notoverlap the preset region by not less than the predetermined amount andsaid second determination unit determines that the predetermined regionhaving, as a reference, the position where the input is performedoverlaps the preset region by not less than the predetermined amount,said control unit controls not to cause said rendering unit to renderthe graphic at the position where the input is performed.
 3. Theapparatus according to claim 1, further comprising: a seconddetermination unit configured to determine, while one input performed bysaid position input unit continues, whether a predetermined regionhaving, as a reference, a position where the input is performed overlapsthe region preset for the graphic already rendered by said renderingunit by not less than a predetermined amount, wherein when said firstdetermination unit determines that the predetermined region having thestart position as a reference does not overlap the preset region by notless than the predetermined amount and said second determination unitdetermines that the predetermined region having, as a reference, theposition where the input is performed overlaps the preset region by notless than the predetermined amount, said control unit controls to removethe already rendered graphic at the position where the input isperformed, and to cause said rendering unit to render a graphicdepending on the position where the input is performed.
 4. A displaycontrol apparatus comprising: a position input unit configured to inputa position on a screen of a display device; a rendering unit configuredto render a graphic according to a locus of the input position input bysaid position input unit; a second determination unit configured todetermine, while one input performed by said position input unitcontinues, whether a predetermined region having, as a reference, aposition where the input is performed overlaps a region preset for thegraphic already rendered by said rendering unit by not less than apredetermined amount; and a control unit configured to control, whensaid second determination unit determines that the predetermined regionhaving, as a reference, the position where the input is performedoverlaps the preset region by not less than the predetermined amount,not to cause said rendering unit to render a graphic.
 5. The apparatusaccording to claim 2, further comprising: a setting unit configured toset, when said rendering unit renders a graphic, a time until therendered graphic is automatically removed, wherein when said seconddetermination unit determines that the predetermined region having, as areference, the position where the input is performed does not overlapthe region preset for the graphic already rendered by said renderingunit by not less than the predetermined amount, said control unitcontrols to reset the time until the already rendered graphic isautomatically removed, which has been set for the already renderedgraphic by said setting unit.
 6. The apparatus according to claim 5,wherein the time until the rendered graphic is automatically removed,which is set by said setting unit, is a time preset for each type ofgraphic to be rendered.
 7. A display control apparatus comprising: aposition input unit configured to input a position on a screen of adisplay device; a rendering unit configured to render a graphicaccording to a locus of the input position input by said position inputunit; a second determination unit configured to determine, while oneinput performed by said position input unit continues, whether apredetermined region having, as a reference, a position where the inputis performed overlaps a region preset for the graphic already renderedby said rendering unit by not less than a predetermined amount; and acontrol unit configured to control, when said second determination unitdetermines that the predetermined region having, as a reference, theposition where the input is performed overlaps the preset region by notless than the predetermined amount, to remove the already renderedgraphic and to cause said rendering unit to render a graphic dependingon the position where the input is performed.
 8. The apparatus accordingto claim 2, wherein when one input performed by said position input unitis an input for rendering a line segment, determination by said seconddetermination unit is not made.
 9. The apparatus according to claim 1,further comprising: an image capturing unit configured to capture anobject; and a storage unit configured to record a moving image capturedby said image capturing unit, wherein when said rendering unit hasrendered a graphic on an image captured by said image capturing unit,said storage unit records the moving image together with the graphic.10. The apparatus according to claim 1, wherein said position input unitinputs a position on the screen by detecting an input on a touch panelarranged on the display device, and the one input is an input from whena finger touches the touch panel until the finger gets off the touchpanel.
 11. A display control apparatus comprising: a position input unitconfigured to input a position on a screen of a display device; arendering unit configured to render a graphic according to a locus ofthe input position input by said position input unit; a firstdetermination unit configured to determine whether a predeterminedregion having, as a reference, a start position of one input performedby said position input unit overlaps a region preset for the graphicalready rendered by said rendering unit; and a control unit configuredto control, when said first determination unit determines that thepredetermined region having the start position as a reference does notoverlap the preset region, to cause said rendering unit to render agraphic according to the locus of the input position, and to control,when said first determination unit determines that the predeterminedregion having the start position as a reference overlaps the presetregion, to remove the graphic already rendered by said rendering unitaccording to the locus of the input position.
 12. A display controlapparatus comprising: a position input unit configured to input aposition on a screen of a display device; a rendering unit configured torender a graphic according to a locus of the input position input bysaid position input unit; a second determination unit configured todetermine, while one input performed by said position input unitcontinues, whether a predetermined region having, as a reference, aposition where the input is performed overlaps a region preset for thegraphic already rendered by said rendering unit; and a control unitconfigured to control, when said second determination unit determinesthat the predetermined region having, as a reference, the position wherethe input is performed overlaps the preset region, not to cause saidrendering unit to render a graphic.
 13. A control method for a displaycontrol apparatus, comprising: a position input step of inputting aposition on a screen of a display device; a rendering step of renderinga graphic according to a locus of the input position input in theposition input step; a first determination step of determining whether apredetermined region having, as a reference, a start position of oneinput performed in the position input step overlaps a region preset forthe graphic already rendered in the rendering step by not less than apredetermined amount; and a control step of controlling, when it isdetermined in the first determination step that the predetermined regionhaving the start position as a reference does not overlap the presetregion by not less than the predetermined amount, to render a graphic inthe rendering step according to the locus of the input position, andcontrolling, when it is determined in the first determination step thatthe predetermined region having the start position as a referenceoverlaps the preset region by not less than the predetermined amount, toremove the graphic already rendered in the rendering step according tothe locus of the input position.
 14. A control method for a displaycontrol apparatus, comprising: a position input step of inputting aposition on a screen of a display device; a rendering step of renderinga graphic according to a locus of the input position input in theposition input step; a second determination step of determining, whileone input performed in the position input step continues, whether apredetermined region having, as a reference, a position where the inputis performed overlaps a region preset for the graphic already renderedin the rendering step by not less than a predetermined amount; and acontrol step of controlling, when it is determined in the seconddetermination step that the predetermined region having, as a reference,the position where the input is performed overlaps the preset region bynot less than the predetermined amount, not to render a graphic in therendering step.
 15. A control method for a display control apparatus,comprising: a position input step of inputting a position on a screen ofa display device; a rendering step of rendering a graphic according to alocus of the input position input in the position input step; a seconddetermination step of determining, while one input performed in theposition input step continues, whether a predetermined region having, asa reference, a position where the input is performed overlaps a regionpreset for the graphic already rendered in the rendering step by notless than a predetermined amount; and a control step of controlling,when it is determined in the second determination step that thepredetermined region having, as a reference, the position where theinput is performed overlaps the preset region by not less than thepredetermined amount, to remove the already rendered graphic and torender a graphic in the rendering step depending on the position wherethe input is performed.
 16. A control method for a display controlapparatus, comprising: a position input step of inputting a position ona screen of a display device; a rendering step of rendering a graphicaccording to a locus of the input position input in the position inputstep; a first determination step of determining whether a predeterminedregion having, as a reference, a start position of one input performedin the position input step overlaps a region preset for the graphicalready rendered in the rendering step; and a control step ofcontrolling, when it is determined in the first determination step thatthe predetermined region having the start position as a reference doesnot overlap the preset region, to render a graphic in the rendering stepaccording to the locus of the input position, and to control, when it isdetermined in the first determination step that the predetermined regionhaving the start position as a reference overlaps the preset region, toremove the graphic already rendered in the rendering step according tothe locus of the input position.
 17. A control method for a displaycontrol apparatus, comprising: a position input step of inputting aposition on a screen of a display device; a rendering step of renderinga graphic according to a locus of the input position input in theposition input step; a second determination step of determining, whileone input performed in the position input step continues, whether apredetermined region having, as a reference, a position where the inputis performed overlaps a region preset for the graphic already renderedin the rendering step; and a control step of controlling, when it isdetermined in the second determination step that the predeterminedregion having, as a reference, the position where the input is performedoverlaps the preset region, not to render a graphic in the renderingstep.
 18. A non-transitory computer-readable storage medium storing aprogram for causing a computer to function as each unit of a displaycontrol apparatus according to claim 1.